1. Field of the Invention
The present invention relates to an FM multiplex broadcasting wave receiver for receiving an FM broadcasting wave carrying audio information and display information multiplexed thereon and for audibly outputting audio information and visually outputting the display information.
2. Description of the Prior Art
Services for of supplying service information such as character information by means of frequency modulation (FM) multiplex broadcasting electric waves are now available, and the supplied service information is displayed on a display device at receiving sides. This service is a so called FM multiplex broadcasting service, and visual information radio receivers are used in daily life by consumers to enjoy such character information as well as radio broadcasting programs.
More specifically, an FM broadcasting station (the service supplying side) sends a multiplex broadcasting electric wave carrying display information such as character or letter and digital information, and consumers (the receiving sides) receive such broadcasting electric waves with an FM receiver equipped with a liquid crystal display device. The FM receiver separates the display information (character or letter and digital informations) from audio information carried by the FM broadcasting electric waves, and converts the separated display information into character codes to display same on the liquid crystal display device. Then, the consumer can read the display information on the liquid crystal display unit of his (her) FM receiver. The FM multiplex broadcasting service supplies display services (visual information) including supplemental program information and independent program information. The supplemental program information includes information relating to a program on the air, for example, such as a title of music on the air and a name of a person who requests such music. The independent program information includes information such as traffic information and weather forecasts, which do not relate to the audio program on the air. The consumer can select the supplemental program information or the independent program information by setting his (her) FM radio receiver.
When a conventional FM radio receiver is set to display the display information, at least one of the independent program information or the supplemental program information is displayed on the display device. Therefore, when a listener sets his (her) FM radio receiver to display an independent program information while he (she) is listening to an audio program, he (she) can not read supplemental program information relating to the audio program to which he (she) is then listening even though such supplemental program information is available. It would be natural for the listener to want to read the supplemental program information to know instantly the title of the music that (she) is then listening to. However, since the supplemental program information is different in its nature from the independent program information, there will be less possibility for the same contents of the supplemental program information to be repeatedly transmitted, and the contents of the supplemental program information will change successively along with the audio program. Therefore, with the conventional FM radio receiver, the listener can miss the chance to read his (her) desired supplemental program information.